Not a typo — there’s an S on the end of World this month because astronomers believe they have discerned an atmosphere on a planet 39 light years away. Closer to home, moons of Saturn and Jupiter are spewing volcanic materials that could lead to microbial life. And right in our own back yard, hurricane season starts early and snow in Denver falls late. It’s a busy weather time, so let’s go Around The WorldS.
Weather On Other Worlds
Astronomers have a way of making far off objects seem close by expressing distances in terms of small numbers. The planet LHS 1140b is 39 light years away — not so far? Well, consider that a light year is more than five trillion miles. So LHS 1140b is ten million times farther away than the sun.
If we’re thinking of colonization, this is one of very few star systems so close to us. But even if we colonize this one, communications with the home world would take an impossibly long time, since light travels at (you guessed it, didn’t you?) the speed of light, so it takes 39 years to send a message. If an announcement of a new birth on LHS 1140b were sent to Earth, a congratulatory reply would arrive when the newborn is an old lady.
Then there’s the practical matter of what it’s actually like on LHS 1140b. For one thing, a year on the new planet takes only a terrestrial day and a half. The planet is probably locked in a tidal dance with one side always facing its sun, making one side of the planet very hot and the other side very cold. Though LHS 1140b may have water and an atmosphere, conditions conducive to terrestrial life are highly unlikely.
LHS 1140b circles a class M dwarf star. Stars of this type comprise about 75% of all stars. Another dwarf star 40 light years from Earth has three planets (out of a total of seven) that are in the habitable zone (where liquid water could exist).
So far, Earthlings have only explored a handful of the billions of stars in our galaxy (The Milky Way), which itself is one of billions of galaxies. Nevertheless, astronomers are finding so many potentially habitable places just in one tiny slice of the universe that you would think some planet, somewhere, would harbor some sort of life.
Oceans On Moons Of Jupiter And Saturn
In our own solar system, scientists working with the Hubble Space Telescope and the Cassini mission to Saturn report eruptions on Saturn’s moon Enceladus (accent on the cel) and Jupiter’s moon Europa that indicate ocean conditions below could harbor life.
These discoveries should not induce fear of invasions by Little Green Men. Any life on these moons will undoubtedly be primitive. It took three and a half billion years after the first microbial life appeared on Earth for hominids to evolve.
Atlantic Tropical Storm Season Starts Early — With Asterisks
Tropical Storm Arlene formed far out in the Atlantic Ocean on April 20, ignoring the National Hurricane Center’s definition of hurricane season (June 1 to November 30, 2017). This is the third year in a row in which there was an out-of-season storm (last year there were two).
The asterisk comes because this was really a hybrid storm, with some tropical characteristics but some that are not.
The atmosphere produces energy of wind (kinetic energy) out of two forms of potential energy. Tropical cyclones convert the energy of warm water into wind: The process of evaporation stores energy in water vapor. When water vapor condenses, the stored energy is released and is converted to wind.
Extra-tropical cyclones convert the potential energy of horizontal temperature differences to wind. Warm on top of cold is a lower energy state than cold and warm side-by-side. The difference is converted to wind.
Many low pressure systems use both forms of potential energy. Arlene was classified sub-tropical, then tropical, then extra-tropical in a single day. Though the temperature in the core of the storm is an indication, there is no way to know exactly what processes were going on in the storm. Designations of tropical, sub-tropical (hybrid), and extra-tropical are, to some extent, subjective.
Considering the very marginal (for tropical cyclones) water temperature in the area and the nearby location of frontal temperature boundaries, Decoded Science considers this a hybrid rather than a tropical system.
Drought Disappears
As of April 25, less than 6% of the continental US was in moderate or severe drought. Graphic courtesy of drought.gov.
At the beginning of winter, about one-third of the US was considered to be in drought. Now, the percentage is down to a record-low 6%. Most of the relief came in California, where the percentage dropped from 85% of the state to 8%.
Rainfall is highly variable from day to day, month to month, and place to place — even places quite close together. In addition, the drought record only goes back to 2000. So it would be premature to draw any conclusion from the data other than to say they are consistent with most theories of climate change, which predict increased precipitation coupled with increases in extreme weather.
Late Season Snowstorm Buries Denver
Last week’s snowstorm dropped a foot of snow on the Denver area. Unusual? Not really. April is the second snowiest month in Denver after March. April of 1933 was the third snowiest month Denver ever had. True, most of the big storms have come earlier in the month, but late April can be a time of wild temperature swings.
While daytime temperatures often get to the balmy 70s, there is enough cold air filtering down from Canada to drop temperatures enough so it can snow. And with the seasonal increase in moisture streaming north from the Gulf of Mexico, the stage is set for late-season storms.
Why Are Hurricanes So Powerful?
Hurricane season is approaching in the Atlantic Basin. When you think about the destructive force of a hurricane, it is a little surprising that 80 mile per hour winds can blow down poorly-constructed buildings, and 160 mph winds can destroy most anything in their path.
A ten mile an hour wind is just a zephyr; 20 miles per hour is a pleasant breeze. But it can be hard to walk against a 40 mile per hour wind; and 80 miles is too much for anyone to make headway against.
An 80 mile per hour wind is only 8 times the 10 mile zephyr. But the power of the wind increases as the cube of the speed. So the 80 mile per hour wind is 512 times as powerful as a ten mile per hour wind. And a category five hurricane of 160 miles per hour is over four thousand times as powerful. That’s why a category five hurricane is so destructive.
Heading Towards Summer
As northern hemisphere days get longer and the sun rises higher in the sky, summer is coming. May will see the maximum of the US tornado season and the yearly maximum of atmospheric CO2. So what’s happening with the weather where you live?
© Copyright 2017 Jon Plotkin, All rights Reserved. Written For: Decoded Science
You may find it a little strange, but such comments as these are especially what I’d like to learn the WHYs about from you: “the power of the wind increases as the cube of the speed.” Also the parts about the conversion of energy from potential to kinetic acid in storms. I’d love to see a slow and steady dissertation on the physics of weather!